kbuild: support W=e to make build abort in case of warning
When developing new code/feature, CONFIG_WERROR is most
often turned off, especially for people using make W=12 to
get more warnings.
In such case, turning on -Werror temporarily would require
switching on CONFIG_WERROR in the configuration, building,
then switching off CONFIG_WERROR.
For this use case, this patch introduces a new 'e' modifier
to W= as a short hand for KCFLAGS+=-Werror" so that -Werror
got added to the kernel (built-in) and modules' CFLAGS.
Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
index 650d0b8..f5f0d6f 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -2,8 +2,8 @@
# ==========================================================================
# make W=... settings
#
-# There are three warning groups enabled by W=1, W=2, W=3.
-# They are independent, and can be combined like W=12 or W=123.
+# There are four warning groups enabled by W=1, W=2, W=3, and W=e
+# They are independent, and can be combined like W=12 or W=123e.
# ==========================================================================
KBUILD_CFLAGS += $(call cc-disable-warning, packed-not-aligned)
@@ -94,3 +94,12 @@
KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN3
endif
+
+#
+# W=e - error out on warnings
+#
+ifneq ($(findstring e, $(KBUILD_EXTRA_WARN)),)
+
+KBUILD_CFLAGS += -Werror
+
+endif
